adb shell pm disable com.google.android.cellbroadcastreceiver
(This is the Wireless Emergency alert app specifically)
Caveat:
CellBroadcast is a feature of the Android Open Source Project that allows devices to receive and display emergency alerts from cellular networks. Learn how to implement CellBroadcast in your device, how to configure the broadcast channels and languages, and how to test the functionality with the CellBroadcast app.
Just live in a country which refuses to acknowledge cell broadcast exists, then you'll die in peaceful silence in the next national emergency while operators take several hours to to send 11 million unicast SMS.